Diagnose and manage vulvar dermatoses, including lichen sclerosus, lichen planus and differentiated VIN

In one line

Lichen sclerosus is a chronic, autoimmune, scarring inflammatory dermatosis of the anogenital skin whose two consequences — progressive architectural destruction and a lifetime vulvar squamous-cell-carcinoma risk of around 3.5–5% — are both substantially preventable by lifelong, individualised ultrapotent topical corticosteroid titrated to normal-looking skin, which makes long-term suppression and malignancy surveillance, not the initial diagnosis, the consultant task.

Mechanism & pathophysiology

The basic histology and clinical recognition of lichen sclerosus are assumed here; the groundwork sits in the Intermediate chapter on lichen sclerosus, and the premalignant vulvar epithelial changes in vulvar epithelial hyperplasia and vulval carcinoma. What a consultant must hold is the immunology that explains both the scarring and the cancer.

Lichen sclerosus (LS) is a T-cell-driven, predominantly T-helper-1, miR-155-dependent inflammatory disease of genital skin and mucosa. The inflammatory infiltrate sits at the dermo-epidermal junction, and the characteristic upper-dermal change is homogenised, hyalinised collagen overlying a band of lymphocytes — sclerosis that is the structural correlate of the clinical scarring. The basement-membrane zone is disrupted, with altered collagen IV and VII; against that disrupted zone, circulating IgG autoantibodies to extracellular matrix protein 1 (ECM1) are found in roughly three-quarters of patients (74% in the original series versus 7% of controls), the strongest single piece of evidence that LS is an acquired autoimmune disorder rather than a purely degenerative one. ECM1 normally regulates basement-membrane and dermal architecture; loss of its function (genetically in lipoid proteinosis, autoimmune in LS) produces the hyaline dermal change.

The disease keeps autoimmune company. Thyroid autoimmunity — Hashimoto thyroiditis and Graves disease — is markedly over-represented, found in about 18.9% of women with LS against 5.1% of male patients, an odds ratio near 2.88. Vitiligo, alopecia areata, pernicious anaemia and type 1 diabetes cluster similarly. The practical inference is to screen symptomatically for thyroid disease and treat LS as a marker of an autoimmune diathesis, not an isolated skin complaint.

The cancer pathway is the part that reorders management. Vulvar squamous cell carcinoma (SCC) arises by two biologically distinct routes. The HPV-associated route runs through high-risk HPV infection, usual-type VIN (now vulvar HSIL) to basaloid or warty SCC in younger women — the same E6/E7-driven inactivation of p53 and Rb that drives cervical disease, and the reason the HPV vaccine is relevant to vulvar as well as cervical cancer. The HPV-independent route runs through lichen sclerosus: chronic inflammation drives clonal expansion of keratinocytes that acquire TP53 mutations, producing differentiated VIN (dVIN) — p16-negative, with aberrant (mutant-pattern) p53 on immunohistochemistry and frequently CK17-positive — which progresses to keratinising SCC in older, post-menopausal women. This is the more dangerous lineage: dVIN is subtle, often unifocal and arising in a field of existing dermatosis rather than as an obvious warty plaque, it progresses to invasion faster than HPV-associated HSIL, and the SCC it produces recurs more often. Up to about 65% of vulvar carcinomas arise on a background of vulvar LS, and SCC is observed in roughly 3.5–7% of women with LS over time — so LS is not a benign itch but a premalignant condition whose malignant potential is HPV-independent, vaccine-irrelevant and surveillance-dependent.

Lichen planus (LP) is an overlapping but separate entity, also a T-cell-mediated interface dermatosis but classically with a lichenoid band of lymphocytes hugging the epidermis, Civatte (apoptotic keratinocyte) bodies, and saw-tooth rete ridges. Its dangerous vulvar form is erosive lichen planus, which destroys the vestibule and vagina (LS spares the vagina), can fuse the introitus and obliterate the vaginal canal, and — as part of the vulvovaginal-gingival syndrome — affects the mouth and gingivae simultaneously. Erosive vulvar LP also carries a malignant-transformation risk, lower than but analogous to LS.

Differentiated VIN — the molecular detail that drives surveillance

dVIN is worth understanding at the level of the cell, because its biology explains why it is both dangerous and easy to miss. Unlike HPV-associated HSIL, where viral E6/E7 oncoproteins functionally inactivate wild-type p53 (so the tumour cells express normal-length p53 abnormally, and p16 is driven block-positive as a surrogate of HPV transcription), dVIN arises from somatic TP53 mutation in keratinocytes chronically inflamed by LS. The mutant p53 may be over-expressed (a strong, continuous "mutant pattern" on immunohistochemistry) or completely absent ("null pattern") — either deviation from the patchy "wild-type" staining of normal epithelium signals dysfunction. Crucially p16 is negative because there is no HPV. The architectural and cytological atypia of dVIN is confined to the basal and parabasal layers with paradoxical surface maturation, so on a casual section it can read as benign reactive or hyperplastic epithelium — which is exactly why a pathologist must be told to look for it, and why p53 and p16 immunohistochemistry are requested explicitly rather than left to routine reporting. CK17 positivity adds support. The consequence for the clinic is that dVIN has a short latency and high rate of progression to invasive keratinising SCC — far higher than HPV-associated HSIL — so its detection is the entire justification for lifelong surveillance of LS.

Assessment

The history is of chronic vulvar itch (LS, often nocturnal and intractable) or soreness and dyspareunia (erosive LP), frequently mislabelled and self-treated as recurrent thrush for years. Ask directly about loss of architecture the woman may have noticed (a "shrinking" or "sealing" introitus, splitting with intercourse or defecation), urinary spraying or deflection (clitoral hood fusion, introital narrowing), and any persistent localised lump, ulcer, raw area or new bleeding — the symptoms that signal malignant change. Screen for personal and family autoimmune disease and for oral or other mucosal symptoms.

Examination is the diagnosis. The hallmarks to document, because they are what change management:

• Lichen sclerosus — porcelain-white, atrophic, "cigarette-paper" crinkled skin in a figure-of-eight around the vulva and perianus (sparing the vagina), with ecchymoses/purpura from fragile dermis, fissuring, and hyperkeratosis. The architectural endpoints are loss of the labia minora (resorption/fusion to the labia majora), fusion of the clitoral hood with clitoral burying (phimosis), midline fusion, and introital stenosis — these are scarring, not active inflammation, and once established they do not reverse with steroid.
• Lichen planus — in the erosive form, glazed bright-red erosions of the vestibule and inner labia, often with a hyperkeratotic Wickham-striae-like white reticulate border, vaginal involvement with synechiae and a serosanguinous discharge, and frequent concurrent oral disease. Architectural destruction (introital and vaginal stenosis) follows.
• Differentiating mimics — vitiligo is depigmentation without textural change, atrophy, scarring or symptoms; chronic dermatitis/lichen simplex is lichenified, leathery, intensely itchy skin from the itch-scratch cycle without the white sclerosis or architectural loss; psoriasis, candidiasis and extramammary Paget disease enter the differential of a red or itchy vulva. The discriminator is the combination of colour change, texture (atrophy/sclerosis) and architectural loss, none of which a simple dermatitis produces.

When to biopsy is the consultant judgement, because LS and LP are usually clinical diagnoses but biopsy is mandatory when malignancy is in play:

• Any focal abnormality within the dermatosis — a non-healing erosion or ulcer, a persistent lump, nodule, warty or hyperkeratotic plaque, fixed erythema, or new bleeding.
• Failure to respond to adequate ultrapotent topical corticosteroid, or rapid relapse on stopping — both can flag underlying dVIN or invasion that the steroid will never clear.
• Diagnostic uncertainty, atypical features, or before starting long-term immunosuppression where the diagnosis is not secure.
• Suspected dVIN or SCC — biopsy generously and from the most abnormal point, because dVIN is histologically subtle and easily under-read; ask the pathologist specifically for p53 and p16 (mutant-pattern p53 with negative p16 supports dVIN; block-positive p16 points to HPV-associated HSIL instead) and CK17 where available.

Investigations beyond biopsy are mostly about the autoimmune company: thyroid function where symptomatic, and a low threshold for screening other autoimmune disease. An HIV test belongs in the SA work-up of any genital dermatosis, because immunosuppression worsens both HPV-associated disease and treatment tolerance.

Reading the biopsy — and the architectural map

How the biopsy is taken decides whether it answers the question. A representative confirmatory biopsy of LS or LP can be a small punch from active, untreated skin (steroid for a few weeks before biopsy normalises the histology and can mask the diagnosis, so biopsy before treating where the diagnosis is uncertain, or from an untreated area). A biopsy taken to exclude malignancy is different: sample the most abnormal point — the thickest, the most fixed, the ulcerated edge — and take enough depth to assess invasion, because a superficial shave can miss early stromal invasion beneath an intact surface. Multiple biopsies of a multifocal or heterogeneous field are legitimate. The pathology request should name the clinical concern (dVIN/SCC on a background of LS) and ask for p53 and p16; a report that says only "hyperkeratosis with chronic inflammation" on a clinically suspicious lesion has not excluded dVIN and warrants re-biopsy or specialist review.

The architectural examination doubles as a prognostic map and a medicolegal record. Photographing or carefully documenting the degree of labial resorption, clitoral burying and introital calibre at baseline lets later review detect progression objectively rather than by impression — important when the question at follow-up is whether scarring is advancing despite treatment (a marker of poor control or non-adherence) and when consent for any future surgery must reference the pre-existing destruction. In erosive LP, documenting vaginal patency and the presence of synechiae is what triggers dilator therapy before the canal seals.

Management

Frame the plan as immediate control → long-term maintenance → lifelong surveillance, and recognise from the outset that the single intervention that changes the natural history — symptom relief, prevention of progressive scarring, and reduction of cancer risk — is continuous individualised ultrapotent topical corticosteroid, not a one-off course.

Immediate / induction. First-line for anogenital LS is clobetasol propionate 0.05% ointment, an induction regimen over about three months: a common schedule is once daily at night for one month, alternate nights for one month, then twice weekly, titrated against response. Ointment, not cream, because it is less irritant and more occlusive. The same ultrapotent topical corticosteroid is first-line for erosive vulvar LP. Set realistic goals: the aim is skin that looks and feels normal (resolution of whiteness, hyperkeratosis, fissuring and ecchymosis), not merely symptom relief — undertreatment leaves smouldering inflammation that scars and may transform. Established architectural change (fused labia, buried clitoris, stenosis) will not reverse with steroid; only active inflammation does.

The South African access reality shapes the prescription. Clobetasol propionate (Dermovate and generics) is registered and marketed in South Africa but is not on the Essential Medicines List — in the public sector it must be privately scripted. The EML lists hydrocortisone 1% for mild eczema and betamethasone 0.1% as the example "potent topical corticosteroid" for moderate-to-severe disease, with the instruction to refer for a dermatologist opinion if non-responsive. The defensible public-sector plan is therefore to start the most potent available agent (betamethasone 0.1% where clobetasol cannot be sourced), escalate access to clobetasol where possible, and refer early — but to name explicitly that substituting a merely potent steroid for an ultrapotent one is a compromise, not equivalence, and one that may leave the disease (and its cancer risk) inadequately suppressed.

Adjuncts. Bland emollients and soap substitutes daily, with rigorous avoidance of soaps, perfumed products, panty-liners and other irritants — irritant contact dermatitis layered on LS is a common reason for apparent treatment failure. Topical calcineurin inhibitors — tacrolimus 0.1% ointment or pimecrolimus 1% cream — are an off-label second-line option for failure of, or intolerance to, corticosteroid; the trial evidence places them below clobetasol in efficacy, and a theoretical malignancy concern (the class carries a regulatory caution) means they should not displace corticosteroid as the agent that demonstrably reduces cancer risk. Erosive LP that fails topical therapy escalates to topical or systemic immunomodulation under specialist (often combined dermatology–gynaecology) care, and vaginal disease needs vaginal corticosteroid and dilator therapy to prevent or treat synechiae.

Maintenance. This is the heart of modern management. After induction, a proactive maintenance regimen — typically clobetasol once or twice weekly, individually titrated to keep the skin normal — is continued indefinitely. The cohort evidence is that women who maintain compliant, individualised topical corticosteroid have near-zero progression to scarring and to SCC/VIN, whereas partially compliant women accumulate both. Stopping when symptoms settle is the commonest management error and the one that allows architecture to be lost and cancer to develop.

Adherence is therefore a clinical target in its own right, and it fails for predictable reasons that are worth pre-empting at the first consultation: unfounded corticosteroid-phobia (patients and prescribers alike fear atrophy from "strong steroids", whereas it is undertreated LS — not the clobetasol — that thins and scars the vulva; used correctly, ultrapotent steroid restores rather than damages the skin), the difficulty of treating an asymptomatic condition once the itch settles, and the practical barriers of cost and supply where the drug is privately funded. Quantifying use — teaching a fingertip-unit dose, showing the woman her own normalising skin at review, and writing the maintenance schedule explicitly rather than "use when needed" — converts a vague instruction into a regimen she can sustain. The reframing that lands is that maintenance is cancer prevention, not symptom suppression.

Surgery has a deliberately limited role. It does not treat the dermatosis and inflamed tissue heals and re-fuses poorly, so surgery is reserved for the complications: division of symptomatic adhesions or release of clitoral phimosis and introital stenosis (in skin first optimised medically, with post-operative steroid and dilators to limit re-fusion), perineoplasty/vestibulectomy for refractory introital narrowing, and — the non-negotiable indication — excision of biopsy-proven dVIN or invasive SCC. Operating on uncontrolled active disease invites recurrence; operating on a missed cancer as if it were an adhesion is the error to design out.

The surgical decisions reward the same sequencing as the medical ones. Release of clitoral phimosis restores sensation and prevents recurrent keratin-pearl entrapment and pseudocyst formation, but is offered only after the surrounding skin is suppressed and the woman accepts that the dermatosis (and so the tendency to re-fuse) persists — continued maintenance steroid and dilator/separation technique post-operatively is what holds the result. Introital stenosis causing dyspareunia or obstructed flow is addressed by Fenton-type perineoplasty or vestibulectomy with flap advancement, again on optimised, biopsy-clear tissue. For dVIN or SCC, the principle is adequate local excision with clear margins (recognising that the surrounding LS-affected field remains at risk, so excision is treatment of the lesion, not cure of the predisposition), and an invasive cancer is then staged and managed on the vulvar-cancer pathway. The recurring trap is treating a surgically-fused, biopsy-unproven introitus as a benign adhesion when a fixed area within it has never been sampled.

Long-term / surveillance. Every woman with LS or erosive LP is in a lifelong surveillance programme for malignant transformation: regular review (commonly 6–12 monthly once stable, sooner if poorly controlled), self-examination education, and a low threshold to biopsy any new focal lesion, non-healing erosion, or treatment-resistant area. dVIN-associated SCC is the lesion that surveillance exists to catch early, when it is still curable by local excision. Co-manage the autoimmune associations and, in SA, anchor follow-up at a level the woman can actually reach, because lifelong tertiary-only review is not deliverable for most patients.

Erosive lichen planus and the vagina — a harder problem

Erosive LP deserves its own management thread because it behaves worse than LS and involves a compartment LS spares. The vulvar erosions respond, like LS, to ultrapotent topical corticosteroid, but vaginal disease needs intravaginal corticosteroid — hydrocortisone foam or pessaries, or compounded preparations — and, critically, vaginal dilators used early and regularly to prevent the synechiae and adhesions that can fuse and obliterate the upper vagina. Once the canal has sealed, restoring it is difficult, recurrence-prone surgery, so prevention is the whole game. Disease refractory to topical therapy escalates to systemic immunomodulation (systemic corticosteroid for flares, then steroid-sparing agents such as methotrexate, mycophenolate or hydroxychloroquine) under combined dermatology–gynaecology care, ideally in a dedicated vulval clinic. Because the vulvovaginal-gingival syndrome spans three mucosal sites, co-management with oral medicine for symptomatic gingival and oral erosive disease is part of holistic care, and the malignant-transformation risk means erosive LP, like LS, is surveyed for life with biopsy of any fixed or non-healing lesion.

A note on irritants and the current debate

The most modifiable amplifier of any vulvar dermatosis is irritant contact dermatitis layered on top of it — from soaps, perfumed washes, wipes, panty-liners and over-washing — and removing these is genuinely therapeutic, not lifestyle advice tacked on. This sits alongside a contemporary and contested claim that chemically-treated intimate-hygiene and sanitary products contain endocrine-disrupting compounds that drive or worsen vulvar disease. The irritant contribution is established and worth acting on; the stronger endocrine-disruptor causation is not, and a consultant presents it as a reasonable precaution (fragrance-free, minimally-processed products) framed by genuine uncertainty rather than as proven mechanism — over-claiming here misleads as much as ignoring the irritant axis does.

Guidelines compared

The substantive disagreements are narrow and worth stating precisely: the bodies agree that ultrapotent topical corticosteroid is first-line and that LS/dVIN carry a real cancer risk; they differ chiefly on the surveillance interval, which BGCS concedes is unsupported by trial data and therefore individualised, and on terminology, where the ISSVD 2015 reinstatement of dVIN matters because a pathology report still using older or LAST-only language can bury the most dangerous diagnosis.

The evidence & the controversy

The single most important shift in LS management over the last two decades is the reframing from "control the itch" to "treat to a target of normal skin, and maintain it for life, to prevent cancer." The Lee, Bradford and Fischer prospective cohort of 507 women is the keystone: women on compliant, individualised maintenance topical corticosteroid had zero SCC or VIN (0 of 357), versus 4.7% (7 of 150) in partially compliant women, alongside far less scarring (adhesions 3.4% vs 40.0%). It is observational, not randomised — one cannot ethically randomise women to undertreatment — and the compliant and non-compliant groups differ in more than their adherence, so a sceptic will note residual confounding. But the effect size, the biological plausibility (suppressed inflammation removes the driver of clonal p53-mutant expansion), and the supporting Cooper cohort (96% symptom improvement, 23% reversal to normal skin, 2.4% SCC) make this the strongest evidence available, and it is the evidence on which the "lifelong maintenance" recommendation rests. The defensible position is that maintenance is recommended on consistent cohort data even though a randomised trial will never exist.

The age-dependence of response (Renaud-Vilmer) sharpens the clinical realism: complete remission with clobetasol falls from ~72% in women under 50 to ~23% in those 50–70 and essentially 0% over 70 — so in the older woman, where the cancer risk is also highest, the goal is durable suppression and vigilant surveillance rather than expecting reversal. This is the population in whom a treatment-resistant area must be biopsied early, not steroid-escalated indefinitely.

The first-line drug choice is also evidence-settled. The Cochrane review of topical interventions found clobetasol clearly superior to placebo (participant-rated improvement RR 2.85), and the head-to-head Funaro trial found clobetasol significantly more effective than tacrolimus 0.1% — which is why calcineurin inhibitors sit second-line despite their steroid-sparing appeal, and why a registrar who reaches for tacrolimus first has the hierarchy inverted.

The live controversies a consultant should be able to weigh: whether asymptomatic LS warrants the same lifelong maintenance as symptomatic disease (the cancer-prevention logic says yes, but adherence to treatment for an asymptomatic condition is poor); how often to survey when no trial defines the interval (individualise to control and risk); and, topically, the recurring claim that fragranced or chemically-treated sanitary and intimate-hygiene products provoke or worsen vulvar dermatoses through irritant or endocrine-disrupting mechanisms — the irritant-contact contribution is real and removing irritants is standard advice, but the stronger endocrine-disruptor claims remain contested and should be presented as such, not as established cause.

The through-line connecting all of this to the foundational pathology — the histological diagnosis of LS, the descriptive recognition of the white atrophic plaque — is the Intermediate lichen sclerosus groundwork; the consultant additions are the autoimmune mechanism, the dVIN cancer pathway, the maintenance-and-surveillance evidence base, and the SA access compromise. The diagnostic skill is assumed; the management judgement is the work.

Landmark trials & key evidence

Exam traps & red flags

• Treating LS as benign and stopping at symptom control. It is a premalignant, scarring disease; intermittent "as-needed" steroid leaves smouldering inflammation that scars and transforms. The standard is treat-to-normal-skin then lifelong maintenance.
• Mistaking a dVIN-associated SCC for a recalcitrant patch. A non-healing erosion, fixed lump, persistent hyperkeratotic plaque or steroid-resistant area in LS is a biopsy, not a stronger steroid — dVIN is subtle and SCC arises HPV-independently in older women.
• Trusting HPV screening or vaccination to exclude vulvar cancer in LS. The LS→dVIN→SCC pathway is HPV-independent and vaccine-irrelevant; a negative HPV test or prior vaccination does not reassure here.
• Reaching for a calcineurin inhibitor first. Tacrolimus/pimecrolimus are second-line; the head-to-head and Cochrane evidence favours clobetasol, which is also the agent shown to reduce cancer risk.
• Confusing LS with LP — and missing vaginal involvement. LS spares the vagina; erosive LP destroys the vagina and vestibule, fuses the introitus, and runs with oral/gingival disease — missing vaginal LP means missing synechiae that obliterate the canal.
• Expecting steroid to reverse architecture. Fused labia, buried clitoris and introital stenosis are scarring; steroid arrests progression but does not undo them — surgery (on optimised skin) addresses the complication.
• Operating on uncontrolled disease. Adhesiolysis or release in actively inflamed, unsuppressed skin re-fuses; medical control first, then surgery with post-operative steroid and dilators.
• Substituting a potent steroid for an ultrapotent one without naming the compromise. In the SA public sector betamethasone 0.1% may be all that is available, but it is not equivalent to clobetasol — say so, and escalate access and referral rather than normalising undertreatment.
• Ignoring the autoimmune company. New thyroid, vitiligo or other autoimmune symptoms warrant screening; LS is a marker of an autoimmune diathesis.
• Under-biopsying erosive LP. It too can transform; a persistent ulcerated or fixed area in erosive LP needs histology, not escalation of topical therapy alone.

Evidence anchors

• Lee, Bradford & Fischer — long-term management of adult vulvar lichen sclerosus, JAMA Dermatol 2015
• Cooper et al — does treatment of vulvar lichen sclerosus influence its prognosis?, Arch Dermatol 2004
• Renaud-Vilmer et al — long-term topical clobetasol and the course of vulvar lichen sclerosus, Arch Dermatol 2004
• Chi et al — topical interventions for genital lichen sclerosus, Cochrane Database Syst Rev 2011
• Funaro et al — clobetasol 0.05% vs tacrolimus 0.1% in vulvar lichen sclerosus, J Am Acad Dermatol 2014
• Oyama et al — autoantibodies to extracellular matrix protein 1 in lichen sclerosus, Lancet 2003
• Del Pino et al — pathways of vulvar intraepithelial neoplasia and squamous cell carcinoma, Histopathology 2013
• Ueda et al — two distinct pathways to vulvar squamous cell carcinoma, J Skin Cancer 2011
• De Luca et al — lichen sclerosus: the 2023 update, Front Med 2023
• Lewis et al — BAD guidelines for the management of lichen sclerosus 2018, Br J Dermatol 2018
• Morrison et al — BGCS vulval cancer guidelines 2023, Eur J Obstet Gynecol Reprod Biol 2023
• Bornstein et al — the 2015 ISSVD terminology of vulvar squamous intraepithelial lesions, Obstet Gynecol 2016
• Ioannides et al — European S1 guidelines on the management of lichen planus, J Eur Acad Dermatol Venereol 2020
• British Society for the Study of Vulval Disease (BSSVD) — Standards of Care for patients with vulval conditions (covering lichen sclerosus and lichen planus).
• South Africa NDoH Standard Treatment Guidelines & Essential Medicines List — hydrocortisone 1% (mild) and betamethasone 0.1% (potent) listed; clobetasol propionate is not an EML item; refer for dermatology opinion where potent topical corticosteroid fails.